The Earth is about 4.5 billion years old. Actual dirt — that is to say, like the stuff in your backyard, not rocks that were once dirt — probably dates to about 2 million years ago. Dirt is young! (Relatively speaking.)

EcoFlight is a group that photographs ecological threats in western states from the vantage point of small airplanes. The idea is to give people a clear picture of the contrast between wilderness and the industrial sites that threaten the ecological health of that wilderness. It's an interesting idea, and certainly results in some amazing photos, such as this shot of evaporation ponds at a potash mining facility near Moab, Utah.

Potash is, essentially, a generic name for several different potassium-laden salts. It's most commonly used as an ingredient in fertilizer, as potassium (along with nitrogen and phosphorous) is one of the three key nutrients plants need to grow. The main environmental threat: How mining potash in the quantities required by the modern agricultural industry could threaten water quality and supplies, and soil quality. It's worth checking out the rest of the photos in the set, which give you a better perspective on where the evaporation ponds sit in context with the local landscape and the Colorado River.

This Potash mine is located 20 miles west of Moab. The mine began underground excavation in 1964 and was converted in 1970 to a solar evaporation system. This mine produces between 700 and 1,000 tons of potash per day.

Water is used from the nearby Colorado River in the production of Potash by a company called Intrepid Potash®. Water is pumped through injection wells into the underground mine which dissolves layers of potash more than 3,000 feet below the surface. The resulting "brine" is then brought to the surface and piped to 400 acres of shallow evaporation ponds. A blue dye is added to the ponds to assist in the evaporation process. These ponds are lined with vinyl to keep the brine from spilling back into the Colorado River. A major by-product of this process is salt. The salt is used for water softening, animal feed and oil drilling fluids as well as many other applications.